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Appendix

  We present a proof of correctness of the signal mapping algorithm detailed in Section 2.3. We use the same notation introduced in Section 2.3.

Claim: This signal layer mapping meets the following constraints:

  1. The network channel limits are observed.
  2. No source Sk transmits more than its total share, wkB.
  3. wk >= wj implies that Ak,n <= Aj,n forall n

Proof: In the proof we refer to line numbers in the algorithm detailed in Figure 6.

  1. tex2html_wrap_inline1549 represents the unused bandwidth available in network channel c. Thus, the check in line 15 guarantees that no source will cause the rate limit of a network channel to be exceeded
  2. tex2html_wrap_inline1553 represents the portion of the bandwidth share of source Sl that has not been utilized by the source. Thus, the decrementing of tex2html_wrap_inline1557 in line 21, along with the check in line 12, guarantees that no source will transmit more that its total share, which is wlB.
  3. The algorithm iterates through the average weight list looking for the largest remaining weight, tex2html_wrap_inline1557 . Now assume that for the two sources in question Sk, and Sj, all signal layers 1,..., n-1 have been mapped to network channels. Next assume that the result of the algorithm's output for layer n is such that muk,n > muj,n

    This along with line 9 imply that

    eqnarray606

    Line 21 of the algorithm implies that in order for (1) to hold the following must also be true:

    tex2html_wrap_inline1573

    which implies that

    wk < wl

    Finally, the arg max directive in line 9 furnishes us with the bootstrap for the induction in the first iteration which completes the proof of statement 3 of the claim. QED



Elan Amir
Sun Aug 17 23:48:24 PDT 1997